Adolescent problem behaviors as predictors of adult alcohol diagnoses.

Young adult alcohol problems based on DIS/DSM III diagnoses were predicted from a number of adolescent risky/antisocial behaviors in a sample of 693 subjects. The number of times an individual was intoxicated before his/her sixteenth birthday was the best indicator of adult alcohol "abuse" and /or dependence, with adolescent fighting, arrests, and lack of participation in religious activities also serving as important problem behavior predictors. Results of correlational and principal-components analyses of adolescent problem behaviors are similar to previous work on Problem Behavior Theory. The results suggest that prevention efforts should begin before adolescence, prior to the time when individuals are exposed to, or begin practicing, adult health-threatening activities.

Infant bouncing: the assembly and tuning of action systems.

We outline a theory of infant skill acquisition characterized by an assembly phase, during which a task-specific, low-dimensional action pattern emerges from spontaneous movement in the context of task constraints, and a tuning phase, during which adjustment of the system parameters yields a more energetically efficient and more stable movement. 8 infants were observed longitudinally when bouncing while supported by a harness attached to a spring. We found an initial assembly phase in which kicking was irregular and variable in period, and a tuning phase with more periodic kicking, followed by the sudden appearance of long bouts of sustained bouncing. This "peak" behavior was characterized by oscillation at the resonant frequency of the mass-spring system, an increase in amplitude, and a decrease in period variability. The data are consistent with a forced mass-spring operating at resonance.

Spatiotemporal linkage in infant interlimb coordination.

Timing and direction of movement of the arms and hands of 7- and 11-month-old infants were examined during bimanual reaching for a transparent cube. Videotape analysis of frames from release of the hands to initial contact of one hand with the cube revealed that hand movement was more often temporally linked for 7-month infants than for 11-month infants. Also, at 7 months, the hands moved toward the cube in the same direction, whereas at 11 months, they moved in opposite (complementary) directions. Thus, although both 7- and 11-month infants perform bimanual reaching, at 7 months the 2 hands are linked both in timing and direction of movement in a fashion different than at 11 months.

The use and effectiveness of maternal scaffolding in mother-infant games.

Maternal behaviors within mother-infant games were examined to determine the amount, type, and functional value of maternal helping behaviors. 17 mother-infant pairs were videotaped on monthly visits from 8 to 16 months as they played 5 separate games. 2 of these games, roll the ball and peekaboo, were analyzed in terms of "rounds" of each game. Results show that dyads play more rounds of both games in the first months that infants perform game-relevant behaviors (e.g., returning a ball, performing uncovering or covering-uncovering). Maternal attention-getting and physical "stage-setting" behaviors occur in the early rounds of both games. In roll the ball, maternal hands-out and reinforcement behaviors increase in the months after the child begins to return the ball, while the percentage of rounds in which dyads play nonreturn variants decreases. Infants are more likely to return a ball when mother holds out her hands than when she does not. Infants are also able to perform returning or uncovering in game contexts before they perform similar behaviors in cognitive tests. The general similarity of findings in the peekaboo and roll-the-ball games, in spite of differences in the amounts of scaffolding, attention-getting, stage-setting, and reinforcement behaviors between the 2 games, indicates that the types and functions of maternal helping behaviors may be generalizable to other contexts of mother-infant interactions.

Phosphorus-31 nuclear magnetic resonance of ethidium complexes with ribonucleic acid model systems and phenylalanine-accepting transfer ribonucleic acid.

The temperature dependence of the 31P NMR spectra of the ethidium complexes with poly(A) X oligo(U) and the 31P spectra of phenylalanine tRNA (yeast) in various molar ratios of ethidium ion (Et) are presented. In the poly(A) X oligo(U) X Et complex, a new peak about 2.0 ppm downfield from the double-helix peak appears. We have assigned this peak to phosphates perturbed by ethidium. The chemical shift of this peak is consistent with the intercalation mode of binding and provides additional support for our hypothesis that 31P shifts are sensitive probes of phosphate ester conformations. The main effect of ethidium on the 31P spectra of tRNAPhe is the broadening of several of the scattered signals. These scattered signals are associated with phosphates involved in tertiary interactions. We propose that these broadened signals arise from phosphates near the Et binding site.

High-resolution phosphorus nuclear magnetic resonance spectroscopy of transfer ribonucleic acids: multiple conformations in the anticodon loop.

The temperature dependence of the 31P NMR spectra of yeast phenylalanine tRNA, E. coli tyrosine, glutamate (2), and formylmethionine tRNA is presented. The major difference between the 31P NMR spectra of the different acceptor tRNAs is in the main cluster region between -0.5 and -1.3 ppm. This confirms an earlier assignment of the main cluster region to the undistorted phosphate diesters in the hairpin loops and helical stems. In addition the 31P NMR spectra for all tRNAs reveal approximately 16 nonhelical diester signals spread over approximately 7 ppm besides the downfield terminal 3'-phosphate monoester. In the presence of 10 mM Mg2+ most scattered and main cluster signals do not shift between 22 and 66 degrees C, thus supporting our earlier hypothesis that 31P chemical shifts are sensitive to phosphate ester torsional and bond angles. At greater than 70 degrees C, all of the signals merge into a single random-coil conformation signal. A number of the scattered peaks are shifted (0.2-1.7 ppm) and broadened between 22 and 66 degrees C in the presence of Mg2+ and spermine as a result of a conformational transition in the anticodon loop. The 31P NMR spectrum of the dimer formed between yeast tRNAPhe and E. coli tRNA 2Glu is reported. This dimer simulates codon-anticodon interaction since the anticodon triplets of the two tRNAs are complementary. Evidence is presented that the anticodon-anticodon interaction alters the anticodon conformation and partially disrupts the tertiary structure of the tRNA.

High resolution phosphorus NMR spectroscopy of transfer ribonucleic acids.

The temperature dependence of the 31P NMR spectra of yeast phenylalanine tRNA, E. coli tyrosine, glutamate (2), and formylmethione tRNA, and bovine liver aspartate (2b) tRNA is presented. The major difference between the 31P NMR spectra of the different acceptor tRNAs is in the main cluster region between -0.5 and -0.3 ppm. This confirms earlier assignment of the main cluster region to the undistorted phosphate diesters in the hair-pin loops and helical stems. In addition the 31P NMR spectra for all tRNAs reveal approximately 16 non-helical diester signals spread over approximately 7 ppm besides the downfield terminal 3'-phosphate monoester. In the presence of 10 mM Mg++, most scattered and main cluster signals do not shift between 22 and 66 degrees C, thus supporting our earlier hypothesis that 31P chemical shifts are sensitive to phosphate ester torsional and bond angles. At greater than 70 degrees, all of the signals merge into a single random coil conformation signal. Measured spin-lattice and spin-spin relaxation times for tRNAPhe reveal another lower temperature transition associated with a conformational change of the anticodon loop besides the thermal denaturation process. A number of the scattered peaks are shifted (0.2--1.7 ppm) and broadened between 22 and 66 degrees C in the presence of Mg++ as a result of this conformational transition. The effects Mg++ and Mn++ ions on the 31P NMR spectra of tRNAPhe have been used to identify some of the scattered signals upfield and downfield from the main cluster signals. The 31P NMR spectrum of the dimer formed between yeast tRNAPhe and E. coli tRNA2Glu is reported. This dimer stimulates codon-anticodon interaction since the anticodon triplets of the two tRNAs are complementary. Evidence is presented that the anticodon-anticodon interaction alters the anticodon conformation and partially disrupts the tertiary structure of the tRNA.

Phosphorus-31 nuclear magnetic resonance of double- and triple-helical nucleic acids. Phosphorus-31 chemical shifts as a probe of phosphorus-oxygen ester bond torsional angles.

The temperature dependence to the 31P NMR spectra of poly[d(GC)] . poly [d(GC)],d(GC)4, phenylalanine tRNA (yeast) and mixtures of poly(A) + oligo(U) is presented. The 31P NMR spectra of mixtures of complementary RNA and of the poly d(GC) self-complementary DNA provide torsional information on the phosphate ester conformation in the double, triple, and "Z" helix. The increasing downfield shift with temperature of the single-strand nucleic acids provides a measure of the change in the phosphate ester conformation in the single helix to coil conversion. A separate upfield peak (20-60% of the total phosphates) is observed at lower temperatures in the oligo(U) . poly(A) mixtures which is assigned to the double helix/triple helix. Proton NMR and UV spectra confirm the presence of the multistrand forms. The 31P chemical shift for the double helix/triple helix is 0.2-0.5 ppm upfield from the chemical shift for the single helix which in turn is 1.0 ppm upfield from the chemical shift for the random coil conformation.

Development of logical search and visual scanning in children.

Children at 5, 6, 7, and 8 years of age were told a story in which a doll traveled through a physical model of a house. The doll had a toy in one room and, then, three rooms after, discovered it to be missing. Tests were made of logical search (i.e., the tendency, when asked to find the toy, to restrict search to the critical area between the rooms). The presence of visual cues that marked the critical area was manipulated, and the visual scanning of these cues was monitored. Children in the two younger groups exhibited virtually no logical search either when cues were absent or present, 7-year-old children showed logical search only when cues were present, and 8-year-old children showed logical search both when cues were absent and present. In the cues-present conditions logical search was related to visual scanning of the cues.

High-resolution phosphorus nuclear magnetic resonance spectra of yeast phenylalanine transfer ribonucleic acid. Metal ion effects and tentative partial assignment of signals.

The temperature and metal ion dependence of the 31P NMR spectra of yeast phenylalanine tRNA is presented, and a tentative assignment of some of the individual phosphate signals is offered. Signals A, C, F, P, and T have been assigned to the magnesium binding site of phosphates by monitoring the magnesium ion dependence in the 31P NMR spectra. In the presence of 10 mM Mg2+, specific paramagnetic line broadening effects are observed for signals A, D, E, and U upon addition of 0.001-0.1 Mn2+ ion per tRNA molecule. Through the combination of the above metal in experiments, X-ray studies, and earlier 1H and 31P NMR studies [particularly the tRNA modification 31P NMR experiments of Salemink et al. [Salemink, P..J.M., Swarthof T., & Hilbers, C.W. (1979) Biochemistry 18, 3477]], an initial assignment of some of these signals is attempted.

Surgical experience with a microscopic transsphenoidal approach to pituitary tumors and non-neoplastic parasellar conditions.

Improved surgical microscopes and intraoperative radiofluoroscopic television have revived the transsphenoidal approach to pituitary tumors. The transsphenoidal approach offers an alternative to craniotomy, and in certain situations it has distinct advantages. The reported experience includes the common pituitary tumors, hypersecreting microadenomas, cerebrospinal rhinorrhea and parasellar aneurysms. The surgical technique, indications and contraindications, and results in 44 transsphenoidal operations are described.